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United States Patent | 5,337,137 |
Ogawa ,   et al. | August 9, 1994 |
A height sensor for determining the height from a surface to be measured on the basis of an optical path length from a light-emitting element to the surface to be measured includes: a first light-emitting element and a second light-emitting element disposed at positions spaced apart from the surface to be measured; a mirror for reflecting at least one of a beam of light emitted from the first light-emitting element and a beam of light emitted from the second light-emitting element; and a light-receiving element for receiving the beams emitted by the first and second light-emitting elements and reflected by the surface to be measured and for outputting a signal corresponding to a quantity of light received. The mirror is arranged to cause respective optical paths of the beams emitted from the first and second light-emitting elements to be brought into close proximity to each other. Another mirror is provided for producing an optical path difference between the respective optical path lengths from the first and second light-emitting elements to the surface to be measured.
Inventors: | Ogawa; Fumio (Yokohama, JP); Nihei; Norio (Kodaira, JP) |
Assignee: | Stanley Electric Co., Ltd. (Tokyo, JP); Bridgestone Corp. (Tokyo, JP) |
Appl. No.: | 997870 |
Filed: | December 29, 1992 |
Jan 09, 1992[JP] | 4-002355 |
Current U.S. Class: | 356/4.07; 267/118; 280/6.159; 280/124.101; 280/124.163 |
Intern'l Class: | G01C 003/08; B60G 011/26 |
Field of Search: | 356/4 280/707 |
4752799 | Jun., 1988 | Stauffer | 354/403. |
4798369 | Jan., 1989 | Geno et al. | 280/707. |
4817922 | Apr., 1989 | Hovance | 280/707. |
4996415 | Feb., 1991 | Tanaka et al. | 250/221. |
5056913 | Oct., 1991 | Tanaka et al. | 356/4. |
5229829 | Jul., 1993 | Nihei et al. | 356/4. |
Foreign Patent Documents | |||
0291394 | Nov., 1988 | EP. | |
0313501 | Apr., 1989 | EP. | |
0419082 | Mar., 1991 | EP. | |
2591330 | Dec., 1987 | FR. |